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Artex ME406 Bad G-Switch

Doing an annual inspection on a 2011 CC18-180 Top Cub. Get to the ELT inspection and using Artex manual to check the G-switch by shorting pins 5 and 12 and trying to set it off by throwing it like a football and it doesn't activate. A few bounces off the Bushwheel didn't help either. Though maybe I was missing something so I called Artex. After leaving messages I finally get someone to answer and find out there is a flat rate for a stuck G-Switch. As quick as they came back with that response to my question I knew they had seen this before. Sure enough New Zealand issued an AD against their ME406 ELTs in that country.https://www.acrartex.com/media/1267396/artex_sn_31.pdfhttp://www.caa.govt.nz/Publications/...0-4_JulAug.pdf
Tried to get an RMA to send it in for repair on Thursday and Friday to no avail so I called just after they opened this morning and got a person who promised to send me an RMA shortly. When asked about this being the same issue the service notice and AD were against he said it was the same and that the flat rate repair will install the new style g-switch. Only $450 to the customer plus shipping. So if you have a ME406 Atrex ELT you might want to test the G-Switch more than once a year. All other tests were fine. Would hate to be slammed into the ground somewhere and this $1200 box in the back doesn't work.

Anything about the installation stand out? Exposure to water or water running down the wires and entering the box?

Web

No, 2011 model airplane that is kept inside and looks almost as it did when it was new. From conversation with Artex and the AD in New Zealand it seems they have had a problem with their G-switches and the owners get to pay for it.

This issue is known. The operation I fly for and wrench in the off season for has seen this issue over and over. We keep a spare ELT on the shelf for this reason. Have had no issues since they have been retrofitted with the new switch.

With the release of their new design, I went ahead and bought one and have had no issues in my 180 Cessna.

Another issue we had was with the "whip" antennas breaking. This was solved by installing the fiberglass rigid antenna. The antenna breakage occurred only on our turbine powered airplanes. Not sure why as they are not high speed turbine aircraft. ........about 30 knots faster than the recips in our fleet that do not break the antenae.

Another issue we had was with the "whip" antennas breaking. This was solved by installing the fiberglass rigid antenna. The antenna breakage occurred only on our turbine powered airplanes. Not sure why as they are not high speed turbine aircraft. ........about 30 knots faster than the recips in our fleet that do not break the antenae.

Originally Posted by wireweinie

..I've seen the broken whips on turbines, also. I think it may have to do with the frequency of the prop blast. Whatever the base cause, the rod antenna does seem to solve the problem.

Web

I believe that you will find that this is due to a change in the natural resonant frequency of the airframe. The old Pratt recips are a big chunk of heavy metal which turn at a low rpm. The new turbines have a low mass turning at high rpm. This changes the natural resonant frequency of the entire airframe which likely shows in the breaking point of that particular antenna. It is possible that you could be finding cracks forming in other places as well, which do not occur in the recip powered versions. The antenna may not break if it was mounted elsewhere on the fuselage. The easiest fix is to do what you have done by using the different type of antenna.

I participated in some high speed Vd dive flight testing on a popular light twin. This particular version had a tendency towards structural failure of the stabilizer at a lower speed than the previously configured production models. After much analysis the cause was determined to be an oxygen bottle which was secured inside the fuselage aft of the baggage compartment. Take out the bottle and the failure speed returned to "normal". As it turned out this particular airplane which was offered with many different combinations of options, had several different limiting Vd speeds depending on how it was equip. As a result of this testing, the Vd speed (Vne is 90% of Vd) was reduced to below the lower of these speeds on all versions to eliminate confusion and to avoid FAA questions which could have created an even bigger can of worms.